1. Field of the Invention
This invention relates to an oil seal device for a rotary engine provided between a rotor and a side housing to prevent lubricating oil on the eccentric shaft side from flowing into the operating chamber.
2. Description of the Prior Art
In a typical prior art oil seal device for a rotary engine, an annular recess is provided in each side of the rotor and a seal ring is fitted in said recess. In the innermost part of the sealing recess is disposed an undulate spring adapted for pressing the seal ring against the side housing. When the rotor makes eccentric rotation, the seal ring is also caused to make corresponding eccentric rotation while scraping off lubricating oil on the sliding face of the side housing. The lubricating oil which has performed cooling of the rotor and lubrication of bearings, gears and such is thus prevented from leaking into the operating chamber from between the side housing and the thrust surface of the rotor. Also, an O-ring or like means is provided radially on the inner or outer peripheral face of the seal ring to keep off the lubricating oil that enters between the seal ring and the sealing recess. Thus, such prior art oil seal device had problems in that an O-ring must be provided for preventing leakage of lubricating oil at or in the surrounding of the spring adapted for pressing the seal ring, that the sealing performance is unstable because the seal ring pressing force of the undulate spring is not uniform, and that the O-ring becomes soon aged as it is exposed to high temperatures, causing unstable sealing performance.